Sounds like a fertilizer overdose to me. Your potting soil may contain fertilizer and if you added more - well, what can I say? I suggest you re-pot with a potting soil that's free of all fertilizer. Give your guys a couple of weeks to recover and then care for them as you usually do. Best And Happy Yardening, Nancy.
Dahlia Leaves Are Curling
Question From: K. WOOD - ALASKA
Q: I'M IN ALASKA, WE START OUR DAHLIA 'S INDOORS, AS OUR LAST FROST IS LATE! MY DAHLIAS HAVE COME UP JUST FINE, UNTIL A FEW DAYS AGO. THE LEAVES ON SOME ARE CURLING. SOME OF THE CURLED LEAVES HAVE MOISTURE IN THEM? WHAT INSECT HAS HIT THEM, FROM THIS TINY BIT OF INFO? I'M JUST SICKENED! I LOOK SO FORWARD TO MY DAHLIAS! THANKS FOR ANY HELP!